--- a/lisp/simple.el	2014-11-21 09:21:50 +0000
+++ b/lisp/simple.el	2014-11-23 11:34:08 +0000
@@ -1598,6 +1598,13 @@
                  (integer :tag "time" 2)
                  (other :tag "on")))
 
+(defcustom suggest-shorter-command-limit 5
+  "Only suggest the equivalent M-x invocation when shorter by this amount.
+If the value is nil, do not suggest shorter M-x key-bindings at all."
+  :group 'keyboard
+  :type '(choice (const :tag "off" nil)
+                 (integer :tag "characters")))
+
 (defun execute-extended-command--shorter-1 (name length)
   (cond
    ((zerop length) (list ""))
@@ -1623,7 +1630,7 @@ defun execute-extended-command--shorter (name typed)
                                       name len)))
                   ;; Don't show the help message if the binding isn't
                   ;; significantly shorter than the M-x command the user typed.
-                  (< len (- max 5))))
+                  (< len (- max suggest-shorter-command-limit))))
       (let ((candidate (pop candidates)))
         (when (equal name
                        (car-safe (completion-try-completion
@@ -1680,7 +1687,8 @@ defun execute-extended-command (prefixarg &optional command-name typed)
                       ((numberp suggest-key-bindings) suggest-key-bindings)
                       (t 2)))))
       (when (and waited (not (consp unread-command-events)))
-        (unless (or binding executing-kbd-macro (not (symbolp function))
+        (unless (or (not suggest-shorter-command-limit)
+                    binding executing-kbd-macro (not (symbolp function))
                     (<= (length (symbol-name function)) 2))
           ;; There's no binding for CMD.  Let's try and find the shortest
           ;; string to use in M-x.